a. Field of Invention
The invention relates generally to a rear body design for a vehicle, and, more particularly to rear rail neutralizing member for minimizing the effect of a moment arm created by the offset of the upper and lower rear rail centroids during rear impact.
b. Description of Related Art
The rear body for a vehicle generally includes a floorpan, rails, body panels, a rear suspension system and a fuel system. On some vehicles, the rear body may include a spare tire, a pivotable door and/or a door track for a sliding door. The rear body also generally includes a rear bumper system at a rear end thereof.
During a rear impact, the rear bumper system and the rails, floorpan and body panels of the rear body are designed to absorb the majority of the impact. While the rear bumper system absorbs a portion of the impact energy in a rear impact, the remaining energy is distributed and absorbed by the rear body. Thus, the design of the rear body plays an important role in the absorption and distribution of forces generated during a rear impact.
In sedan and wagon uni-body vehicles including an all-wheel drive (AWD) option and low step-over height for customer ease of ingress and egress, these rear impact absorption characteristics require the large rear rail system offset to be taken into account in the design of the rear body. This is because in such vehicles, the moment arm created by the two height levels of the rear rail system forward and aft sections is greater than that for wagon uni-body vehicles or typical sedans without the AWD option.
Commonly owned U.S. Pat. No. 6,053,566, which is incorporated herein in its entirety by reference, describes a rear body assembly for motor vehicles including rear rails having a plurality of convolutions for absorbing energy upon a rear impact.
While many advances have been made in rear rail systems for improved rear impact absorption characteristics, as evidenced by the rear body assembly described in U.S. Pat. No. 6,053,566, there remains a need for a system or method for minimizing the moment arm created by the two height levels of the rear rail system forward and aft sections for sedans or other vehicles including an AWD option and/or similar rear impact absorption requirements. Specifically, there remains a need for a system or method for minimizing and/or controlling deformation of a vehicle rear body, which is robust in design, simple to install and service, and which is economically feasible to manufacture.
The invention solves the problems and overcomes the drawbacks and deficiencies of prior art rear rail systems by providing a rear rail neutralizing member for minimizing the effect of the offset between rear rail upper and lower centroids.
Thus an exemplary aspect of the present invention is to provide a rear rail neutralizing member for minimizing the effect of a moment arm created by rear rail upper and lower centroids during a rear impact.
Another aspect of the present invention is to provide a rear rail neutralizing member for minimizing and/or controlling deformation of a vehicle rear body, which is robust in design, simple to install and service, and which is economically feasible to manufacture.
The invention achieves the aforementioned exemplary aspects by providing a rear impact absorption system for a motor vehicle. The system includes a rear body assembly including at least one longitudinally extending rear rail including first and second portions having first and second respective heights relative to a generally horizontal plane, the first height being greater than the second height. The system further includes a neutralizing member operatively connectable to the rear rail to bridge the first and second heights of the rear rail so as to minimize the effect of a moment arm created by the first and second heights during a rear impact.
For the system described above, the neutralizing member may include first and second sections, each including a pair of laterally extending flanges disposed generally orthogonal to the respective first and second sections. Each of the flanges may face an inner surface of the neutralizing member. The first section may be connected to the second section and disposed generally orthogonal to the second section at the connection so as to provide a predetermined distribution of impact energy during a rear impact.
The invention further provides a neutralizing member including first and second sections each including a pair of laterally extending flanges disposed generally transverse to the respective first and second sections. Each of the flanges may face an inner surface of the neutralizing member. The first section may be connected to the second section and disposed generally transverse to the second section at the connection so as to provide a predetermined distribution of impact energy during a rear impact.
For the neutralizing member described above, the second section may include a curved convex member generally centrally disposed along a longitudinal first length of the second section and a curved concave channel generally centrally disposed along a longitudinal second length of the second section. The combined first and second lengths may be less than a total length of the second section. The convex member and the concave channel may provide a predetermined distribution of impact energy during a rear impact. The curved convex member may merge with the curved concave channel. The second section may include a pair of additional laterally disposed flanges oriented vertically or horizontally for facilitating alignment of the neutralizing member relative to the rear rail.
In another aspect, the invention yet further provides a neutralizing member connectable to a rear body assembly of a motor vehicle so as to minimize the effect of a moment arm created by the offset of first and second heights of respective first and second portions of a rear rail during a rear impact. The neutralizing member may include the components and configuration discussed above, and described in further detail below.
The invention also provides a method for minimizing the effect of a moment arm created by the offset of first and second heights of first and second portions of a rear rail during a rear impact on a motor vehicle. The method includes the step of providing a neutralizing member connectable to the rear rail to bridge the first and second heights of the rear rail. The neutralizing member may include first and second sections each including a pair of laterally extending flanges disposed generally transverse to the respective first and second sections, each of the flanges facing an inner surface of the neutralizing member. The first section may be connected to the second section and disposed generally transverse to the second section at the connection so as to provide a predetermined distribution of impact energy during a rear impact. The method further includes the step of installing the neutralizing member into the rear rail.
For the method described above, the neutralizing member may include the components and configuration discussed above, and described in further detail below.
Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.